Outer Limits 4x4 Board

Having problems with my 6.5 n/a. At first it was tacking loudly and had no power under load. Took it to a shop and had the injectors and injector pump rebuilt. I also had the single filter replaced with a double unit. It was a bit better but at 2000rpm when under load would hit a brick wall and actually start to slow down and hold at around 1800RPM.

I have an old fuel pump that was a bit sus but had been working in the past so decided to try that. Things got worse and it would not go past 1800 under load (this meant 30-40kmh going up hills.

I brought a new carter lift pump that is 7psi and 72gph. It is now almost back to normal but hits a wall at 2300rpm under heavy load and holds there till the load comes off.

The auto is very tired but I would think it would silp if anything and let the engine spin, not bog it down.

I have a theroy that goes something like this;
Injector pump was rebuilt to the upper limits, according to the manifactors specs, allowing for more fuel (so the rebuilder tells me). The injectors were rebuilt to match the injector pump. With this in mind, the additional filter adding to flow restriction and the new fuel requirement of the injector pump and injectors, the 7psi pickup pump prior to the filters is no longer powerful enough to supply the required fuel.

Sound plausable???

Any ideas? Did the shop charge me $4400 and stuff the job on the injection pump? Is the dual filter causing too much restriction to the flow and/or pressure? Should I add my old pickup pump after the filters to help with the supply? Anyone???

Why not start with simple test ( I'm not a Chevy expert .. ) try one filter ( I thought it not gonna make the diference but give a try ) and a ride test ..

Nev62 wrote:Having problems with my 6.5 n/a. At first it was tacking loudly and had no power under load. Took it to a shop and had the injectors and injector pump rebuilt. I also had the single filter replaced with a double unit. It was a bit better but at 2000rpm when under load would hit a brick wall and actually start to slow down and hold at around 1800RPM.

I have an old fuel pump that was a bit sus but had been working in the past so decided to try that. Things got worse and it would not go past 1800 under load (this meant 30-40kmh going up hills.

I brought a new carter lift pump that is 7psi and 72gph. It is now almost back to normal but hits a wall at 2300rpm under heavy load and holds there till the load comes off.

The auto is very tired but I would think it would silp if anything and let the engine spin, not bog it down.

I have a theroy that goes something like this;
Injector pump was rebuilt to the upper limits, according to the manifactors specs, allowing for more fuel (so the rebuilder tells me). The injectors were rebuilt to match the injector pump. With this in mind, the additional filter adding to flow restriction and the new fuel requirement of the injector pump and injectors, the 7psi pickup pump prior to the filters is no longer powerful enough to supply the required fuel.

Sound plausable???

Any ideas? Did the shop charge me $4400 and stuff the job on the injection pump? Is the dual filter causing too much restriction to the flow and/or pressure? Should I add my old pickup pump after the filters to help with the supply? Anyone???

4400 for an IP rebuild? FARRRRRR OUT MAN.

http://cgi.ebay.com/ebaymotors/GMC-CHEV ... enameZWD1V
http://cgi.ebay.com/ebaymotors/6-5-6-5L ... enameZWDVW


do youi know what a new pump and injectors is worth from the states?

Jes

The filters would have to have a problem to cause a restriction like that.
It does, however, sound like you're running out of fuel.
If you took it in for this problem in the first place then take it back!

Is the engine missfiring and running rough when it wont rev anymore? If so its a fuel supply problem, either from restrictions, lack of supply or air enetring the system.

Have you checked full thottle at the pump. Is the lever touching the stopper bolt?


Will this rever higher in nuetral? Try hooking up a external fuel source and see what happens.


Andy

are you sure 7psi is enough. My old sd33 runs the equivelent of a holley black which is set at about 16psi i think and is mounted near the tank.

I ended up having to run a slightly larger fuel line as well, IT has sorted my issues with the old girl and shes std.

Maybe try a larger fuel line to see if it helps. Psi does pressure but maybe still not enough volume when the goveners open up.

CHeers

pongo wrote:are you sure 7psi is enough. My old sd33 runs the equivelent of a holley black which is set at about 16psi i think and is mounted near the tank.

I ended up having to run a slightly larger fuel line as well, IT has sorted my issues with the old girl and shes std.

Maybe try a larger fuel line to see if it helps. Psi does pressure but maybe still not enough volume when the goveners open up.

CHeers

you need higher pressuer with veggie oil

Always check, change filters 1st. If it is on veggie oil they block filter real quick (Iv seen 60 kilometers from loosened gunk)
Tyr a bit of clear line in fuel run temporarily to ensure no air bubbles, (Air can get sucked in thru hose or end )

Bazzle

my patrol used to do this, i thought it was a fuel issue, but turns out it wasn't getting enough air. i took the top off my air filter and took it for a strap around the block and bingo, like driving a new car.

rover1 wrote:my patrol used to do this, i thought it was a fuel issue, but turns out it wasn't getting enough air. i took the top off my air filter and took it for a strap around the block and bingo, like driving a new car.

A diesel will be blowing a lot of black smoke if air is the issue.

Ruffy wrote:The filters would have to have a problem to cause a restriction like that.
It does, however, sound like you're running out of fuel.
If you took it in for this problem in the first place then take it back!

It is going back tomorrow!

Have you checked full thottle at the pump. Is the lever touching the stopper bolt?

Yep, get full thottle

Will this rever higher in nuetral? Try hooking up a external fuel source and see what happens

Yep will rev all day long in netural or no load

are you sure 7psi is enough

GM specs are for 4-6psi so 7psi is more than enough.

Psi does pressure but maybe still not enough volume when the goveners open up.

Pump is rated at 72gph

No veggie oil and no air found.

No black smoke.

What tyres are on this? Are they at correct pressure? We have had patrols that wont go through a full run on our dyno because of low pressured centipedes.


Andy

Problem FOUND! It is the new dual filter setup I bye-passed them to see what would happen and low and behold, the power is back. It still seems a bit wanting but is now increasing RPM under heavy load (steep hill and the boot put in). This is actually better then before the work done to it (would just hold and not increase under very heavy load). \

Now the question is do I put my two carter pumps inline (near the fuel tank were one is now), or place one in the engine bay after the filters?

Nev, i run a carter at the tank, one filter in the engine bay, and a fuel pressure reg (6-9psi, running around 7 aswell) after the filter. My pump is modded and the injecters to suit (pump cost $1200 to buy outright and modded, injecters were $80each to rebuild, you may have been ripped a bit). Good thing you've found the problem though.

The disappointing part was that I found the source of the problem and not a well know diesel shop that I payed a bucket load to:?

Thats gotta suck Kiss principlal keep it simple stuip old one but can be soo true also had a problem like this at work totaly diffrent vehicle passed press test ok flow was a bit down more testing ended up being the tank the holes with the baffels near the pick up were blocked causing it so suck dry and no fuel was going to suggest this but you found it good work.

in the shorty mk i had, i had a huge drama with inconsitent fuel issues , ended up being carpet strings sucked up the tank pick up. What amazed us is htf did they get there.